Afterburner apparatus having lined burner can

ABSTRACT

Afterburner apparatus for use with an internal combustion engine and including a burner can having a structural casing lined with a low thermal capacity material which forms a flame chamber having an inlet for connection with the exhaust manifold of the engine and an outlet for egress of exhaust which has been burned in the chamber. A pilot burner is mounted in the chamber and means is provided for controlling the rate and ratio of fuel and air thereto in response to various engine speeds and conditions. Thus a flame is produced in the chamber which is insulated against direct contact with the structural casing to thereby reduce quenching of the flame upon contact with the walls of the chamber and provide for relatively rapid heating of the chamber to the desired high temperature for burning the combustibles in the exhaust.

ilriite States atermt Cornelius Feb. 15,1972

[541 AFTERBURNER APPARATUS HAVING LINED BURNER CAN [21] Appl. No.: 13,034

[52] US. Cl. ..60/30, 23/277 C [51] Int. Cl ..F01n 3/14 [58] Field of Search ..60/29, 30; 23/2 C, 277 C [56] References Cited UNITED STATES PATENTS 2,203,554 6/1940 Uhri ..23/277 C 3,166,895 1/1965 Slayter. ..60/30 3,189,418 6/1965 Gary.... ..60/30 3,203,168 8/1965 Thomas ..60/30 3,233,697 2/1966 Slayter ..60/30 3,273,971 9/1966 Baddorf ..23/277 C AIR CRANKC/LS E Rosenlund ..60/ 30 Thomas ..60/ 29 Primary Examiner-Douglas Hart Attorney-Fulwider, Patton, Rieber, Lee & Utecht [57] ABSTRACT Afterburner apparatus for use with an internal combustion engine and including a burner can having a structural casing lined with a low thermal capacity material which forms a flame chamber having an inlet for connection with the exhaust manifold of the engine and an outlet for egress of exhaust which has been burned in the chamber. A pilot burner is mounted in the chamber and means is provided for controlling the rate and ratio of fuel and air thereto in response to various engine speeds and conditions. Thus a flame is produced in the chamber which is insulated against direct contact with the structural casing to thereby reduce quenching of the flame upon contact with the walls of the chamber and provide for relatively rapid heating of the chamber to the desired high temperature for burning the combustibles in the exhaust.

8 Claims, 5 Drawing Figures AFTERBURNER APPARATUS HAVING LINED BURNER CAN BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to afterburner devices for use with internal combustion engines.

2. Description of the Prior Art Afterburner apparatuses have been proposed which include insulated burner cans having air and fuel delivered thereto for maintaining a flame therein at a sufficiently high temperature to burn combustibles in the exhaust from an internal combustion engine. However, such afterburner devices generally have their burning chambers formed by a metal liner and the flame is in direct contact with such liner, thereby tending to quench the flame during operation, thereby rendering combustion of the combustibles in the exhaust somewhat incomplete.

SUMMARY OF THE INVENTION The afterburner apparatus of present invention is characterized by a burner can which is lined with a material having a low thermal capacity and which forms a flame chamber into which air and fuel is delivered to maintain a high-temperature flame for consuming the combustibles included in the exhaust from an internal combustion engine. The low thermal capacity material serves as an insulator to prevent conduction of heat from the flame chamber and flame contact therewith produces a relatively minor amount of quenching to thereby enable relatively complete combustion of the combustibles.

An object of the present invention is to provide an afterburner apparatus of the type described wherein the flame chamber is heated to a relatively high temperature in a comparatively short period of time after actuation of such apparatus.

Another object of the present invention is to provide an afterburner apparatus of the type described wherein the flame chamber is formed, in part, by a forwardly projecting flame tube and the air and fuel are introduced to the forward ex tremity thereof to initiate combustion relatively early in the exhaust flow stream whereby combustion will be complete before the exhaust leaves the flame chamber to thereby prevent overheating of the tailpipe.

Another object of the present invention is to provide an afterburner apparatus of the type described wherein the burner can may be substituted for the muffler of a conventional automobile.

These and other objects and the advantages of the present invention will become apparent from a consideration of the following detailed description when taken in conjunction with the following drawing.

DESCRIPTION OF THE DRAWING FIG. 1 is a top plan view, partially broken away, of an afterburner apparatus embodying the present invention;

FIG. 2 is a horizontal sectional view, in enlarged scale, taken along the centerline of the afterburner apparatus shown in FIG. 1;

FIG. 3 is a vertical sectional view taken along the line 3-3 of FIG. 2; and

FIGS. 4 and 5 are vertical sectional views taken along the lines 44 and 55, respectively, of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT The afterburner apparatus of present invention includes a burner can C having a metallic structural shell 19 which is lined with a low thermal capacity material, generally designated 21 (FIG. 2) that forms a combustion chamber 23. Projection forwardly from the combustion chamber 23 is a burning tube, generally designated 31, that includes an outer shell 33 and an inner liner, generally designated 35, of low thermal capacity material. The flame tube liner 35 forms a flame passage 36 which cooperates with the combustion chamber 23 to form a composite flame chamber within which combustion is completed. A pilot burner, generally designated 39, is mounted in the forward extremity of the burning tube 31 and has air and fuel supplied thereto by means of a carburetor, generally designated 43. Thus, the afterburner can C may be connected with the exhaust pipe 47 of an internal combustion engine and when the engine is started, the carburetor means 43 will deliver air and fuel to the pilot burner 39 and ignition thereof will produce a flame within the passage 36 which will be propagated rearwardly into the combustion chamber 23. The liners 21 and 35 will absorb substantially no heat to enable the passage 36 and chamber 23 to be heated to a relatively high temperature almost instantaneously to thereby reduce quenching of the flame and assure combustion of the relatively high percentage of combustibles contained in the exhaust while the engine is warming up. The burning exhaust gases will flow rearwardly through the passage 36 and will pass rearwardly through the flame chamber 23 wherein combustion is substantially completed.

The liners 21 and 35 are made from a low thermal capacity material whereby they will absorb little or no heat and will act as insulators to prevent conduction of heat from the passage 36 and combustion chamber 23 to thereby assure relatively rapid heating of the composite flame chamber formed thereby. A material which is particularly effective for such liners 21 and 35 is a ceramic fiber insulation sold under the trade name KAOWOOL by Babcock and Wilcox Co. of Augusta, Ga. Such ceramic material, when untreated, is relatively soft and flexible on the order of a coarse wool or cotton and must be treated with a hardening agent to cause it to assume any degree of rigidity.

The chamber liner 2! includes an inner layer 58 which has been treated with a hardening or bonding agent to cause it to maintain a configuration forming the flame chamber 23. The inner layer 55 is wrapped with an untreated low heat absorption ceramic fiber material 59 to enhance the insulating characteristics and the entire low thermal capacity material 21 is encased in the metal casing 19. In the particular embodiment shown, the casing 19 is in the form ofa pair of clamshell sections which are clamped together around the liner material 21.

Referring to FIG. 2, spaced a short distance back of the front wall of the burner can C is a front partition, generally designated 65, which cooperates with such wall to form an entry chamber 67. The partition includes a plurality of perforations 69 therein for passage rearwardly therethrough of gases to the combustion chamber 23.

A longitudinal tube fitting 71 projects through the partition 65 and includes a cap 73 on its front end which is disposed in direct confrontation with the burning tube passage 36 for receiving impingement of the hot gases from such passage. The tube fitting 71 includes a plurality of perforations 75 therearound for passage of rearwardly flowing hot exhaust gases.

Spaced a short distance ahead of the rear wall of the burner can is a rear partition, generally designated 81, which cooperates with the backwall of such burner can C to form an outlet chamber 82 and includes a plurality of perforations for passage rearwardly therethrough of exhaust gases. A tailpipe fitting, generally designated 85, projects forwardly through the partition 81. The front extremity of the tailpipe fitting 85 is capped by a perforated cover 89 and the walls of such tailpipe fitting 85 include a plurality of perforations 91 for passage of exhaust gases.

The burning tube 31 is formed with an offset at to accommodate the space available under the body of a conventional automobile. The liner material 35 includes an inner layer 94 treated with a hardening agent to cause it to assume a rigid condition and a relatively flexible wrap 92 which is untreated. A conical shaped perforated diffusor 93 is mounted in the front extremity of the passage 36.

Extending longitudinally through the burner can C is a temperature-sensing tube 95 which is anchored on its rear extremity to the casing 19 by means of an adjustment nut assembly, generally designated 97. The sensing tube 95 projects forwardly through the entire combustion chamber 23 and is freely extendible and retractable in response to temperature changes.

Referring to FIG. 1, a structural sheath 99 has its rear extremity carried by the front wall of the burner can C and has its forward extremity carried by a mounting bracket [03 which mounts the carburetor 43. Telescoped within the sheath 99 is a slide rod 105 (FIG. 2) which transmits forces from the sensing tube 95 to a control apron 107 which controls air and fuel proportioning from the carburetor 43 in response to the temperature in the flame chamber 23.

A fuel conduit 111 and an air conduit 113 lead from the carburetor 43 to the pilot burner 39. A spark plug 117 is mounted in the pilot burner 39 for providing a spark thereto for igniting the air and fuel mixture therein.

A blower 121 is connected with the carburetor 43 by means of a conduit 123 and such blower receives air from an air filter 125 and draws blowby fumes from the crankcase 127.

in operation, when the engine is started, the carburetor 43 will deliver air and fuel to the pilot burner 39 and the spark plug 117 will ignite the air and fuel mixture. The resultant flame produced within the flame passage 36 of the flame tube 31 will rapidly heat such flame passage and induce combustion of contaminants contained in the relatively rich exhaust being delivered from the exhaust pipe 47 during engine warmup. Since the liner 35 has substantially no heat-absorbing capability, there will be little or no quenching of the flame and the entire heat of combustion will be available for incinerating the combustibles in the exhaust.

The burning gases will travel rearwardly through the flame passage 36 and will impinge on the flame plate 73 mounted in the burner can C to be dispersed across the inlet chamber 67. The burning gases will then pass rearwardly through the perforated partition 65 to be distributed relatively evenly across the chamber 23 and also muffle engine noise.

Combustion of the air and fuel will be completed within the combustion chamber 23 and the rearwardly traveling gases will pass through the perforated rear partition 81 and into the outlet chamber 82 and finally out the tailpipe fitting 27. It is of particular importance that the flame path through the flame passage 36 of the flame tube 31 and through the combustion chamber 23 is of sufficient volume to assure that combustion of the gases has been completed before they pass into the tailpipe fitting 27 thereby preventing emission of partially consumed contaminants and preventing overheating of the tailpipe which may initiate ignition of adjacent combustible materials.

As the temperature in the combustion chamber 23 increases, the temperature-sensing tube 95 will expand to control the carburetor 43 to adjust the rate of introduction of air and fuel to the pilot burner 39 to maintain the desired temperature in the combustion chamber 23.

From the foregoing it will be clear that the afterbumer device of present invention provides a flame chamber that will be heated relatively rapidly and will absorb little or no heat to thereby reduce quenching of the flame to enable complete combustion of the combustibles in the exhaust. Further, the afterbumer can may be readily substituted for the muffler on a conventional automobile without major redesign of the vehicle.

Various modifications and changes may be made with regard to the foregoing without departing from the spirit of the invention.

lclaim:

l. Afterburner apparatus for use with an internal combustion engine, said apparatus comprising:

a burner can including a low thermal capacity liner means forming a flame chamber having an inlet for connection with the exhaust manifold of said engine and an outlet for egress of exhaust which has been burned in said chamber said liner means including a relatively soft, low coefficient of heat transfer insulating material which is treated on its inner surface to form a rigid inner layer;

a structural casing encasing said low thermal capacity material;

coupling means for connecting said can to said exhaust manifold; and

carburetor means connected with said burner can for delivering air and fuel to said chamber whereby said air and fuel will maintain a flame in said chamber for burning combustibles included in the exhaust from said mainfold and the amount of quenching resulting from said flame contacting the wall of said chamber will be relatively minor.

2. Afterburner apparatus as set forth in claim 1 that includes:

a pilot burner disposed in said can and connected with said carburetor means.

3. Afterburner apparatus as set forth in claim 1 wherein said burner can is adapted to be substituted for the muffler of a conventional motor vehicle and wherein:

said burner can includes a forwardly projecting flame tube for connection with said exhaust manifold, and having said carburetor means connected with the forward extremity thereof, said pipe including a relatively low thermal capacity material forming an exhaust passage whereby the exhaust gases will be introduced to said burner can relatively soon after it has exited said exhaust manifold to thereby reduce cooling thereof.

4. Afterburner apparatus as set forth in claim 1 wherein:

said structural casing is of a relatively high thermal capacity.

5. Afterburner apparatus as set forth in claim 1 wherein:

said burner can includes diffusion means disposed in the flow path through said chamber.

6. Afterburner apparatus as set forth in claim 1 wherein:

said insulating material is a ceramic fiber insulation.

7. Afterburner apparatus as set forth in claim 1 wherein:

said insulating means is on the order of KAOWOOL.

8. Afterburner apparatus as set forth in claim 1 wherein:

said insulating material is a refractory fiber treated on its inner surface with binder means.

4: s: w a: =t= 

1. Afterburner apparatus for use with an internal combustion engine, said apparatus comprising: a burner can including a low thermal capacity liner means forming a flame chamber having an inlet for connection with the exhaust manifold of said engine and an outlet for egress of exhaust which has been burned in said chamber said liner means including a relatively soft, low coefficient of heat transfer insulating material which is treated on its inner surface to form a rigid inner layer; a structural casing encasing said low thermal capacity material; coupling means for connecting said can to said exhaust manifold; and carburetor means connected with said burner can for delivering air and fuel to said chamber whereby said air and fuel will maintain a flame in said chamber for burning combustibles included in the exhaust from said mainfold and the amount of quenching resulting from said flame contacting the wall of said chamber will be relatively minor.
 2. Afterburner apparatus as set forth in claim 1 that includes: a pilot burner disposed in said can and connected with said carburetor means.
 3. Afterburner apparatus as set forth in claim 1 wherein said burner can is adapted to be substituted for the muffler of a conventional motor vehicle and wherein: said burner can includes a forwardly projecting flame tube for connection with said exhaust manifold, and having said carburetor means connected with the forward extremity thereof, said pipe including a relatively low thermal capacity material forming an exhaust passage whereby the exhaust gases will be introduced to said burner can relatively soon after it has exited said exhaust manifold to thereby reduce cooling thereof.
 4. Afterburner apparatus as set forth in claim 1 wherein: said structural casing is of a relatively high thermal capacity.
 5. Afterburner apparatus as set forth in claim 1 wherein: said burner can includes diffusion means disposed in the flow path through said chamber.
 6. Afterburner apparatus as set forth in claim 1 wherein: said insulating material is a ceramic fiber insulation.
 7. Afterburner apparatus as set forth in claim 1 wherein: said insulating means is on the order of KAOWOOL.
 8. Afterburner apparatus as set forth in claim 1 wherein: said insulating material is a refractory fiber treated on its inner surface with binder means. 